The present invention relates in general to padlocks, and more particularly to combination padlocks of the exposed shackle type having rotatable tumbler elements to be rotatably adjusted by the owner to a predetermined combination of angular positions by rotation of some external mechanism, thereby releasing the internal locking mechanism from the shackle so that the shackle can be retracted through a sufficient stroke outwardly of the padlock body to attain an unlocking position.
Heretofore, many types of combination padlock mechanisms have been devised, wherein rotation of a dial and dial knob assembly through a selected combination of turns in alternating opposite directions to different predetermined angular positions conditions a locking mechanism within the padlock casing or body to release a locking shoulder or dog from the shackle. This permits the shackle to be shifted through a selected stroke outwardly of the padlock casing until a shorter leg of the shackle is completely withdrawn from the lock casing whereupon the shackle can be swung about the axis of the longer leg still held in the padlock casing to shift the shackle to an open position. One of the typical types of internal locking mechanisms employed in such exposed shackle combination padlocks is to provide a plurality of tumbler wheels rotatably journaled on a common axis or post and having some sort of lost motion coupling between the successive tumbler wheels to achieve successive positioning of a peripheral gate in each of the tumbler wheels at a preselected position permitting a sufficient range of movement of a locking device to achieve retraction of the locking mechanism from interlocking relation with the shackle. However, these prior combination padlocks have usually been of rather expensive construction, frequently employing many cast parts and expensive cast padlock bodies or casings, if the locks are constructed in such manner as to provide reasonable protection against accidental operation by impact forces resulting from dropping of the lock or hitting of the lock against another object, and if the construction of the lock is such as to provide reasonably long reliable operational life under heavy use as encountered on school lockers, and similar applications.
An object of the present invention is the provision of a novel exposed shackle padlock construction wherein most of the padlock components are formed from stamped or shaped sheet metal parts and wherein the manner of manufacture and construction of the lock achieves considerably economies in the manufacture of a padlock of reliable and yet inexpensive construction. Another object of the present invention is the provision of a novel exposed shackle combination padlock construction of the type described in the immediately preceding paragraph, which is highly resistant to accidential unlocking operation of the padlock, and wherein the set of tumbler wheels can be readily set during manufacture to a number of different positions relative to the dial knob to easily establish a large number of different combinations for the padlock.
Another object of the present invention is the provision of a novel exposed shackle combination padlock construction having a key override feature facilitating opening of the combination padlock by a master key under the control of a custodian or the like to enable unlocking of the padlock when the combination has been forgotten or the owner of the padlock is not available to operate the padlock.
Yet another object of the present invention is the provision of a novel exposed shackle padlock construction having an operating mechanism similar to that of the above described combination padlocks but which is operable by a ward key rather than by manipulation of a dial and knob assembly to effect release of the padlock shackle.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating preferred embodiments of the invention.